Two directional plasma charge transfer device

ABSTRACT

A Two Directional Plasma Charge Transfer Device utilizing an ionizable gas in an enclosure having a primary channel and a plurality of secondary channels extending laterally therefrom, an input electrode which can be directly or capacitively coupled to the gas, a plurality of transfer electrodes coated with a dielectrical material on opposite internal walls of the enclosure offset from one another throughout the length of the channels and arranged so that upon application of input signals, the gaseous discharge transfers successively between subsequently offset transfer electrode pairs by the transfer of the electric charge on the wall coating of the electrode which results from the gaseous discharge, first along the primary channel and subsequently laterally from the direction of its original travel so that the device may be used preferably as a graph display or as a two directional shift register.

United States Patent [191 Kessler [451 Feb. 12,1974

[ Two DIRECTIONAL PLASMA CHARGE TRANSFER DEVICE [75] Inventor: Clarence W. Kessler, Oakwood,

Ohio

[73] Assignee: The National Cash Register Company, Dayton, Ohio [22] Filed: Aug. 28, 1972 [21] Appl. No.: 284,396

[52] US. Cl 313/188, 313/217, 313/220 [51] Int. Cl. H0lj 61/06 [58] Field of Search 313/220, 201, 188, 217

[56] References Cited UNITED STATES PATENTS 2,847,615 8/1958 Engelbart 313/201 X Primary Examiner-Palmer C. Demeo Attorney, Agent, or FirmJ, T. Cavender; Albert L. Sessler, .lr.; Edward Dugas [57] ABSTRACT A Two Directional Plasma Charge Transfer Device utilizing an ionizable gas in an enclosure having a primary channel and a plurality of secondary channels extending laterally therefrom, an input electrode which can be directly or capacitively coupled to the gas, a plurality of transfer electrodes coated with a dielectrical material on opposite internal walls of the enclosure offset from one another throughout the length of the channels and arranged so that upon application of input signals, the gaseous discharge transfers successively between subsequently offset transfer electrode pairs by the transfer of the electric charge on the wall coating of the electrode which results from the gaseous discharge, first along the primary channel and subsequently laterally from the direction of its original travel so that the device may be used preferably as a graph display or as a two directional shift register.

3 Claims, 5 Drawing Figures TWO DIRECTIONAL PLASMA CHARGE TRANSFER DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention utilizes the plasma charge transfer phenomenon to form a graph display and/or two directional shift register memory.

2. Description of the Prior Art and Cross The use of gaseous discharge devices and the transfer of trapped charges resulting from the discharge is now well recognized and in the physical construction of a device using this principle, an ionizable gas is contained within an enclosure, having a plurality of transfer electrodes coated with a dielectric material aligned parallel but offset one another on opposite side walls of an enclosure. The device is serially addressed by applying electrical pulses to an input electrode, forming with the first or nearest offset transfer electrodes, the first gaseous cell within a device. By the proper application of a potential on the electrodes, the gas between cells, formed by pairs of electrodes, is discharged and the electric charge, formed or trapped on the coated walls of the electrodes, is used to transfer this gaseous discharge throughout the length of the device. Alternatively any input serially addressed into the device can be held in place at any time before a serial transfer out by applying an alternating potential between any oppositely adjacent electrode pairs forming a cell. The input in these devices held or as serially transferred can be considered digital information and, as such, the device can be used as a shift register but preferably the device is used as a display panel since light in the form of glowing dots is a by-product of the plasma discharge.

As an example of the foregoing devices, reference is made to the U. S. application to William E. Coleman and Clarence W. Kessler entitled Plasma Charge Transfer Device filed May 22, 1972, Ser. Number 255,547, which application is incorporated by reference herein.

SUMMARY OF THE INVENTION The plasma charge transfer device constructed in accordance wth the teaching of this invention utilizes the transfer electrode pair system to serially transfer plasma cells along a channel enclosure by transferring trapped charges as described in the foregoing U. S. Patent Application of Coleman and Kessler and in addition thereto has transfer electrodes located so that the input information in the serially loaded primary channel may be transferred laterally. This is accomplished by providing the primary channel with a plurality of lateral channels each having transfer electrodes and corresponding in number to the number of groups of pairs of transfer electrodes utilized to shift serially in the primary channel. For example, in the device disclosed two pairs of transfer electrodes forming four bit positions in the primary channel will connect to one lateral channel, the second of four bit positions will connect to a second lateral channel, etc., will the last pair of the transfer electrodes of each bit position extending into it respective channel to tranfer the trapped charge thereto,

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing the invention in one practical version, illustrating to advantage the location of the transfer electrodes and the primary and lateral channels;

FIG. 2 is a plan view showing the lateral channels in phantom and their relationship with the transfer electrodes and primary channel;

FIG. 3 is a cross-sectional view taken along line 3*3 of FIG. 2;

FIG. 4 is a cross-sectional view of FIG. 2 taken along line 4-4; and

FIG. 5 is a perspective view with a portion of one-half of the panel being removed to show in detail the loca' tion of electrodes relative to the gas cavity.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings, the plasma charge transfer device utilizing the teachings of the present invention, is indicated in its entirety as 10, and shown in FIG. 1 as expanded or exploded for the purpose of clarity but in a finished form is shown as a panel (FIGS. 3, 4 and 5) with two substrates 12 of any suitable dielectric material, such as clear glass, on which four conductors 14 are placed on inside walls 16 of each substrate along the outer edges forming a continuous conductor with the plurality of furcations or transfer electrodes in pairs numbered 1-4 extending laterally. Two layers of dielectric material 18 for coating the electrodes overlay the furcations and sandwiched between the two layers of dielectric material 18, are two flat sheets of opaque glass cavity forming material 12 which together with the substrates I2 and dielectric coating material 18 form the enclosure channels 20 to contain the ionizable gas, such as neon and nitrogen, at a predetermined pressure.

As shown in these figures, the channels are formed with a primary channel 20, and a plurality (four shown) of secondary channels 20a-d extending laterally from the primary channel.

In the embodiment shown, the transfer electrodes 14, on the inside wall, and coated with the dielectric material, form gas cells means dischargable when a suitable potential is applied and by alternating the applied potential step by step along the length of the channel, the gaseous discharge is transferred successively in cells throughout the length.

As more fully explained in the U. S. Pat. Application to Willian E. Coleman and Clarence W. Kessler, filed May 22, I972, Ser. No. 255,547, the charge transfer device 10 utilizes an input electrode i, either directly or capacitively coupled to the ionizable medium, and the capacitively coupling of the electrodes 14 to the ionizable medium by the dielectric coating material 18, the additive effect of the wall voltage formed by the trapped charged, so that a gaseous discharge occurs when two oppositely offset electrodes have a charge which is additive to the applied voltage, and the principle of transferring this trapped charge electrode to electrode, plus the principle that a gaseous discharge will not occur with this same voltage is applied between any two oppositely offset electrodes which do not have the charge trapped on the wall of at least one of the electrode pairs.

As explained in the foregoing application, the input electrode i, forms with the first electrode 1, the first gaseous discharge cell and then by utilization of the trapped charge, the bit of information or a dot of light, may be transferred down the electrode pairs, 12, 2-3,

and 3-4, until the bit of information or dot of light is held between the electrode pairs 3-4. As also explained in the foregoing application, so long as the applied voltage is alternated between any one of the cells formed by the opposite pairs of transfer electrodes, but particularly between those electrodes'3 and 4, the bit of information may be held indefinitely therebetween. As also explained in the foregoing application, if a gaseous discharge is finally held between the last cell formed by the two oppositely offset electrodes 3 and 4, this same gaseous discharge can be transferred to the second group of electrodes 1-4 and to the third group of electrodes 1-4, etc. throughout the length of the primary channel which length in the embodiment shown in FIG. 2, comprises four groups of electrode pairs 1-4.

At the end of the primary channel there is also provided an erase electrode e, also shown directly coupled to the gas to clear the last load position and if desired, means may be provided for detecting the discharge in the last gas cell as a means for reading information out. Alternatively, if the device is used as a display, the erase electrode e is simply used to clear the display.

As depicted clearly in FIG. 1, and shown as phantom in FIG. 2, the four secondary channels 20a-d open up into the primary channel 20, and it is to be noted, transfer electrodes 3 and 4 of each of the alternate pairs of electrodes 1-4, extend into each channel by furcations 30, 31 extending normal to the main portions of electrodes 3,4. These two furcations 30, 31 form the first gas cell in each of the secondary channels and are located so as to cooperate with four additional transfer electrodes, A, B, C, and D, formed parallel to the conductors 14 on opposite sides of the secondary channels in alternating sequence. These latter electrodes are formed and coated in the manner similar to the four electrodes 1-4, and are the means of transferring the trapped charges on the walls along the length of each of the secondary channels. The mode of operation of these four transfer electrodes is identical to the mode of operation of the original primary electrodes 1-4, except in this instance, the direction is a lateral to the direction of the original input. Thus, for example, if a dot of light in the form of the discharing cell is held in the first of the four electrodes 3, 4, this discharge can be transferred down the first of lateral secondary channels 20a. And, as in the same manner as the primary channel 20, if there is no dot of light in this first group of electrodes, there will be no discharge loaded into the secondary channel 20a. And, as in the case of the primary channel, the secondary channels are provided with an erase electrode e directly coupled to the gas to clear the last load position in a manner identical to the method of operation of electrode e at the end of the primary channel.

It should be noted also in connection with this invention, that while, as shown in FIGS. 3 and 4, the conductor ends of conductors 14 are not shown exposed, they can be exposed in the manner similar to that in connection with the foregoing Coleman and Kessler application by offsetting the ends of the substrates 12 to permit convenient connection of conductors to suitable drivers and other electronics.

Also, while the input electrode i is shown directly connected to the gas, i.e., uncoated, it can be coated and be capacitively coupled to the gas in the manner described in connection with the foregoing application of Colemen and Kessler.

Also, if desired, and as described in the foregoing application, keep-alive electrodes may be used. These electrodes are normally capacitively coupled to the gas, and connected to a source of alternating pulses of sufficient magnitude to ionize the gas within the channel. Their purpose is to insure sufficient ionized particles are always available at the first cell formed by the input electrode i, and the transfer electrode 1 and as more fully explained in the foregoing Coleman and Kessler application.

lt should also be noted that while only one set of transfer electrodes A, B, C, and D is shown, it is not the intent to limit the device to that configuration. lndeed, in a practical display version of the present device, there will be several hundred such transfer electrodes A, B, C and D with each corresponding A, B, C, and D electrode commonly connected.

In order to more fully understand the operation of this display device as a two directional display a bried description of the serial loading of the device with information will now be described.

The serially addressing of the primary channel, of course, will be as described in the foregoing application of Coleman and Kessler entitled Plasma Charge Transfer Device filed May 22, 1972, Ser. No. 255,547. The serial sequence will be first entered into the primary channel with the clocking of the conductors for furcations 1, 2, 3 and 4 operating in the load mode with the input conductor i being activated at the appropriate time. Once the entire primary channel is loaded, it is put into a hold mode with the electrodes 3-4 having an alternating potential applied thereto. This, of course, includes furcation 30 forming part thereof. This hold mode is repeated for some time to establish equilibrium in the cell formed by these electrodes. Once equilibrium is established, the trapped charges are ready to be shifted down one position into the secondary channels where the sequence will start utilizing the electrodes 3-4 (furcation 30 thereof) and electrodes A-B and then C-D etc., in the same manner as the wall charges are transferred across the primary channel. "'xfifipein't where the informafi onin the primary channel has been transferred to electrodes C-D the secondary channels can be placed in a hold mode, that is, the alternating potential is applied to electrodes C-D holding the charge. At this time more information can be loaded into the primary channel with the sequence again repeated and then shifted down from the primary channel to the secondary channels. In the meantime, of course, the information in the first channels C-D can be shifted down to later positions.

The loading mode can be continued until a display is completely filled, i.e., the primary and secondary channels are filled with essential information. At the appro priate time the information can be erased by the function of the erase electrodes e.

When the device is used as a two directional shift register memory, the sequence for serially addressing the memory is essentially the same as described above. When the memory is completely filled, however, with essential information and it is desired to read the information out, serially, the device is operated in the reverse mode. That is to say, the information in each of the secondary channels will be transferred in a reverse direction and caused to enter the primary channels through electrodes 3-4 in the primary channel which corresponds to the first position in the secondary channels. For example, any information in channel a in the nth position would be shifted back to the n-l position ultimately being transferred back to the CD positions such as shown in FIG. 2 with the hold mode sequence being used at every transfer point between the groups of four electrodes in the same manner as when the information was shifted into the register originally. Thus, after the information in channel 20a that had been sustained in the cell formed by electrodes CD, is transferred C to B then B to A and then 4 to 3, it can be held between electrodes 4-3 until it is transferred to the right (as shown in FIG. 2) to the output electrode.

What is claimed is: 1. A Two Directional Plasma Charge Transfer Device comprising:

an enclosure having a primary channel containing an ionizable medium: a plurality of secondary channels extending laterally therefrom and connecting therewith: an input electrode means within said primary channel;

'a plurality of transfer electrode means arranged in alternating sequence and offset one from another on opposite sides of the inside walls of the primary channel and the secondary channels and capacitively coupled to said medium, the transfer electrode means in the primary channel arranged and coupled in groups of two pairs and with the last two electrode means of each of the group of pairs ex tending into the secondary channels;

said input electrode means and said transfer electrode means arranged so that once the medium discharges between the input electrode and the nearest transfer electrode means by the application of electrical energy to the said electrode means, the application of sequentially applied electrical energy to said transfer electrode means will cause a plasma discharge between certain of said transfer electrode means and shift said plasma discharging along the length of said primary channel and then subsequently along the length of the secondary channels.

2. The Two Directional Plasma Discharge Transfer Device as claimed in claim 1 further including output means for clearing the charges in the channels.

3. The Plasma Charge Transfer Device as claimed in claim 1 wherein the transfer electrode means aare coated with dielectric material which material forms the dielectric for the capacitive coupling of the electrode means to the medium. 

1. A Two Directional Plasma Charge Transfer Device comprising: an enclosure hAving a primary channel containing an ionizable medium: a plurality of secondary channels extending laterally therefrom and connecting therewith: an input electrode means within said primary channel; a plurality of transfer electrode means arranged in alternating sequence and offset one from another on opposite sides of the inside walls of the primary channel and the secondary channels and capacitively coupled to said medium, the transfer electrode means in the primary channel arranged and coupled in groups of two pairs and with the last two electrode means of each of the group of pairs extending into the secondary channels; said input electrode means and said transfer electrode means arranged so that once the medium discharges between the input electrode and the nearest transfer electrode means by the application of electrical energy to the said electrode means, the application of sequentially applied electrical energy to said transfer electrode means will cause a plasma discharge between certain of said transfer electrode means and shift said plasma discharging along the length of said primary channel and then subsequently along the length of the secondary channels.
 2. The Two Directional Plasma Discharge Transfer Device as claimed in claim 1 further including output means for clearing the charges in the channels.
 3. The Plasma Charge Transfer Device as claimed in claim 1 wherein the transfer electrode means aare coated with dielectric material which material forms the dielectric for the capacitive coupling of the electrode means to the medium. 